Coupling structure for expansion unit output shaft and driven-side transmission shaft

ABSTRACT

An expansion unit ( 4 ) for converting an expansion energy of pressure-increased steam into a rotation energy of an output shaft, wherein a cover member ( 26 ) is provided on the casing outer surface of the expansion unit ( 4 ). The cover member ( 26 ) has a function of sealing the end section of an output shaft ( 23 ) protruding beyond the casing outer surface against the outside and a function of recovering steam led out from the casing and has its pressured reduced after the conversion. The end section of the output shaft ( 23 ) provided inside the cover member ( 26 ) and a driven-side transmission shaft ( 119 ) disposed outside the cover member ( 26 ) are coupled with each other via a magnet type shaft coupling ( 120 ) so as to be able to transmit power, whereby the output shaft ( 23 ) and the driven-side transmission shaft ( 119 ) can be coupled without steam in the expansion unit leaking outside.

FIELD OF THE INVENTION

The present invention relates to a structure of connection between anoutput shaft of an expander, particularly, a member in which anexpansion energy of a raised pressure vapor serving as an operatingmedium is converted into a rotating energy for the output shaft, and atransmitting shaft of a driven member.

BACKGROUND ART

Such an expander is conventionally used, for example, as a motor in aRankin cycle. There is such a conventionally known connection structurein which an end of an output shaft is located to protrude to the outsidefrom a casing of an expander and is connected to the transmitting shaftthrough a gear device (for example, see Japanese Utility ModelPublication No.1-33768).

Of course, a seal member is mounted in an output shaft-insertion boreprovided in the casing, but the following problem is encountered: Theraised-pressure vapor may be leaked to the outside through between theseal member and the output shaft, and such leakage of the vapor to theoutside results in a reduction in amount of the operating medium,thereby detracting the function of the Rankin cycle and failing themaintaining of the performance.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a connectionstructure of the above-described type, wherein the output shaft of theexpander and the transmitting shaft of the driven member can beconnected to each other to prevent the leakage of the raised-pressurevapor serving as the operating medium to the outside.

To achieve the above object, according to the present invention, thereis provided a structure of connection between an output shaft of anexpander and a transmitting shaft of a driven member, comprising a covermember mounted on an outer surface of a casing of an expander in whichan energy of expansion of vapor having a raised pressure is convertedinto a rotating energy for an output shaft, the cover member having afunction of sealing an end of the output shaft protruding on the outersurface of the casing against the outside and a function of recoveringvapor discharged from the casing and having a dropped pressure after theconversion, and a connecting member for connecting the end of the outputshaft located within the cover member and the transmitting shaft of thedriven member disposed outside the cover member, so that a power can betransmitted.

With the above arrangement, the output shaft and the transmitting shaftof the driven member can be connected to each other with the peripheryof the end of the output shaft being sealed, so that the power can betransmitted. In addition, the raised-pressure vapor leaked from thesealed portion of the output shaft in the casing is recovered by thecover member and hence, cannot be leaked to the outside. Further, therecovered vapor is dropped in pressure within the cover member and fedto the condenser, for example, along with the dropped-pressure vapordischarged from the casing. Thus, it is possible to avoid a reduction inamount of the operating medium to maintain the function of the Rankincycle and the performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a waste heat recovering device foran internal combustion engine;

FIG. 2 is a vertical sectional view of an expander, taken along a line2—2 in FIG. 6;

FIG. 3 is a sectional view of one example of a structure of connectionbetween an output shaft and a transmitting shaft;

FIG. 4 is an enlarged sectional view of portions around a rotationalaxis shown in FIG. 2;

FIG. 5 is a sectional view taken along a line 5—5 in FIG. 2;

FIG. 6 is an enlarged sectional view of essential portions, taken alonga line 6—6 in FIG. 2;

FIG. 7 is a diagram showing sectional shapes of rotor chamber and arotor;

FIG. 8 is a front view of a vane body;

FIG. 9 is a side view of the vane body;

FIG. 10 is a sectional view taken along a line 10—10 in FIG. 8;

FIG. 11 is a front view of a seal member;

FIG. 12 is an enlarged view of the portions around the rotational axisshown in FIG. 5; and

FIG. 13 is a sectional view similar to FIG. 3, but showing anotherexample of a structure of connection between the output shaft and thetransmitting shaft.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, a waste heat recovering device 2 for an internalcombustion engine 1 utilizing a Rankin cycle includes an evaporator 3for generating a vapor having a raised temperature and a raisedpressure, which is an operating medium, namely, araised-temperature/pressure vapor, utilizing a waste heat from theinternal combustion engine 1, e.g., an exhaust gas as a heat source, anexpander 4 in which an energy of expansion of theraised-temperature/pressure vapor is converted into a rotating energyfor an output shaft, a condenser 5 for liquefying a vapor having adropped temperature and a dropped pressure, namely,dropped-temperature/pressure vapor discharged from the expander 4 afterthe conversion, and a supply pump 6 for supplying a liquid, e.g., waterfrom the condenser 5 to the evaporator 3.

The expander 4 has a special structure and is constructed as describedbelow.

Referring to FIGS. 2 to 6, a casing 7 is comprised of first and secondhalves 8 and 9 made of a metal. Each of the halves 8 and 9 comprises amain body 11 having a substantially circular recess 10, and a circularflange 12 integral with the main body 11. A substantially elliptic rotorchamber 14 is defined by superposing both the circular flanges 12 one onanother with a metal gasket 13 interposed therebetween. An outer surfaceof the main body 11 of the first half 8 is covered with a deepbowl-shaped main body 16 of a shell-shaped member 15, and an expansionchamber 20 is defined between both of the main bodies 11 and 16 of theshell-shaped member 15 and the first half 8 by superposition of acircular flange 17 integral with the main body 16 on the circular flange12 of the first half 8 with a gasket interposed therebetween. Further,an outer surface of the man body 11 of the second half 9 is covered witha stepped cylindrical main body 27 of a cover member 26, and adropped-temperature/pressure vapor recovery chamber 29 is defined bysuperposition of a circular flange 28 integral with the main body 27 onthe circular flange 12 of the second half 9 with a gasket G interposedtherebetween. The recovery chamber 29 communicates with the condenser 5through a duct 30. The four circular flanges 12, 12, 17 and 28 arefastened at a plurality of circumferential points by bolts 19.

The main bodies 11 of the halves 8 and 9 include hollow bearing tubes 21and 22 protruding outwards on their outer surfaces, respectively, and alarger-diameter portion 24 of a hollow output shaft 23 extending throughthe rotor chamber 14 is rotatably supported on the hollow bearing tubes21 and 22 with a metal bearing 25 interposed therebetween. Thus, an axisL of the output shaft 23 passes through an intersection between longerand shorter diameters in the substantially elliptic rotor chamber 14.

A circular rotor 31 is accommodated in the rotor chamber 14, and ashaft-mounting bore 32 in the center of the rotor 31 and alarger-diameter portion 24 of the output shaft 23 are fitted with eachother, with meshed portions 33 provided between the rotor 31 and thelarger-diameter portion 24. Thus, a rotational axis of the rotor 31 ismatched with the axis L of the output shaft 23 and hence, is designatedby “L”.

A plurality of, e.g., twelve (in the present embodiment) slot-shapedspaces 34 are defined at circumferentially equal distances in the rotor31 to extend radially from the shaft-mounting bore 32 about therotational axis L. Each of the spaces 34 is of a substantially U-shapewithin a phantom plane perpendicular to opposite end faces 35 of therotor 31, so that it has a small circumferential width and continuouslyopens into the opposite end faces 35 and an outer peripheral surface 36of the rotor 31.

First to twelfth vane piston units U1 to U12 of the same structure aremounted within the slot-shaped spaces 34 for reciprocal movement in aradial direction as described below. In each of the substantiallyU-shaped spaces 34, a stepped bore 38 is defined in a portion 37defining an inner periphery of the space 34, and a stepped cylindermember 39 made of a ceramic material is fitted into the stepped bore 38.The cylinder member 39 has a smaller-diameter portion a whose end faceabuts against the outer peripheral surface of the larger-diameterportion 24 of the output shaft 23, and a smaller-diameter bore bcommunicating with a through-bore c opening into the outer peripheralsurface of the larger-diameter portion 24. A guide tube 40 is disposedoutside the cylinder member 39 so as to be located coaxially with themember 39. The guide tube 40 has an outer end locked in an opening ofthe space 34 located in the outer peripheral surface of the rotor 31,and an inner end fitted into a larger-diameter bore portion d of thestepped bore 38 to abut against the cylinder member 39. The guide tube40 also has a pair of elongated grooves e extending in an opposedrelation from its outer end to near its inner end and facing the space34. A piston 41 made of a ceramic material is slidably received in alarger-diameter cylinder bore f in the cylinder member 39, and has a tipend usually located in the guide tube 40.

As shown in FIGS. 2 and 7, a section B of the rotor chamber 14 in aphantom plane A including the rotational axis L of the rotor 31comprises a pair of semi-circular sectional portions B1 with diameters gopposed to each other, and a quadrilateral sectional portion B2 formedto connect opposed ends of the diameters g of the semi-circularsectional portions B1 to each other and to connect the other opposedends to each other. The section B is formed into a shape substantiallysimilar to a racing track. In FIG. 7, a portion shown by a solid lineindicates the largest section including a longer diameter, while aportion shown in part by a two-dot dashed line indicates the smallestsection including a shorter diameter. The rotor 31 has a section Dslightly smaller than the smallest section including the shorterdiameter of the rotor chamber 14, as shown by dotted line in FIG. 7.

As clearly shown in FIGS. 2, 6 and 8 to 11, a vane 42 is comprised of avane body 43 in the form of a substantially U-shaped plate, and a sealmember 44 in the form of a substantially U-shaped plate mounted to thevane body 43.

The vane body 43 includes a semi-arcuate portion 46 which is opposed toan inner peripheral surface 45 formed by the semi-circular sectionalportions B1 of the rotor chamber 14 and is usually spaced apart from theinner peripheral surface 45, and a pair of parallel portions 48 whichare opposed to opposed inner end faces 47 formed by the quadrilateralsectional portion B2 and are usually spaced apart from the opposed innerend faces 47. A rectangular U-shaped notch 49 is provided in an end ofeach of the parallel portions 48; a quadrilateral blind bore 50 opensinto a bottom surface of the notch 49, and a short shaft 51 is mountedat a location displaced from each of the notches 49 to the end toprotrude outwards. In addition, a U-shaped groove 52 is definedcontinuously in outer peripheries of the semi-arcuate portion 46 and theparallel portions 48 to open outwards, and communicates at its oppositeends with the notches 49, respectively. Further, a pair of projections53 in arched section are provided on flat surface areas of thesemi-arcuate portion 46. The projections 53 are disposed so that an axisL1 of a phantom column formed by the projections 53 is matched with astraight line bisecting the distance between the parallel portions 48and bisecting the semi-arcuate portion 46 circumferentially. Inner endsof the projections 53 protrude slightly into a space between theparallel portions 48, and a gap 54 between the projections 53 extendsinto the semi-arcuate portion 46.

The seal member 44 is formed of PTFE and includes a semi-arcuate portion55 sliding on the inner peripheral surface 45 formed by thesemi-circular sectional portions B1 of the rotor chamber 14, and a pairof parallel portions 56 sliding on the opposed inner end faces 47 formedby the quadrilateral sectional portion B2. A pair of resilient claws 57are provided on an inner peripheral surface of the semi-arcuate portion55 so as to be curved inwards.

The seal member 44 is mounted in the U-shaped groove 52 in the vane body43, and a spring 58 is fitted into each of the blind bores 50. Further,a roller 59 having a ball bearing structure is mounted to each of theshort shafts 51. Each of the vanes 42 is slidably accommodated in eachof the slot-shaped spaces 34 in the rotor 31. In this case, theprojections 53 of the vane body 43 are located within the guide tube 40,with their opposite side portions located in the elongated grooves e inthe guide tube 40, respectively, whereby inner end faces of theprojections 53 can be put into abutment against outer end faces of thepistons 41. The rollers 59 are rollably engaged in elliptic annulargrooves 60 defined in opposed inner end faces 47 of the first and secondhalves 8 and 9, respectively. The elliptic shape of the annular grooves60 has an analogous relationship to the elliptic shape of the rotorchamber 14.

As clearly shown in FIG. 6, the semi-arcuate tip end face 61 of thesemi-arcuate portion 46 of the vane body 43 is usually spaced apart fromthe inner peripheral surface 45 of the rotor chamber 14, and theparallel portions 48 are usually spaced apart from the opposed inner endfaces of the rotor chamber 14, respectively, by the cooperation of therollers 59 and the annular grooves 60 with each other, thereby providinga reduction in friction loss. In addition, as clearly shown in FIG. 2,the parallel portions 56 of the seal member 44 are brought into closecontact with the opposed inner end faces 47 of the rotor chamber 14 bythe repulsing forces of the springs 58, and the semi-arcuate portion 55is brought into closed contact with the inner peripheral surface 45 bythe resilient claws 57 pushed between the vane body 43 and the innerperipheral surface 45 within the rotor chamber 14. Thus, a goodsealability is provided between the vane 42 and the rotor chamber 14.

Referring to FIGS. 2 and 4, the larger-diameter portion 24 of the outputshaft 23 includes a thicker portion 62 supported on the metal bearing 25of the second half 9, and a thinner portion 63 extending from thethicker portion 62 and supported on the metal bearing 25 of the firsthalf 8. A hollow shaft 64 made of a ceramic material is received in thethinner portion 63, so that it can be integrally rotated with the outputshaft 23. A stationary shaft 65 is disposed inside the hollow shaft 64and comprises a larger-diameter solid portion 66 fitted in the hollowshaft 64 to extend within the axial thickness of the rotor 31, asmaller-diameter solid portion 69 fitted in a bore 67 provided in thethicker portion 62 of the output shaft 23 with two seal rings 68interposed therebetween, and a thinner hollow portion 70 extending fromthe larger-diameter solid portion 66 and fitted in the hollow shaft 64.A seal ring 71 is interposed between an outer peripheral surface of anend of the hollow portion 70 and the inner peripheral surface of thehollow bearing tube 21 if the first half 8.

An end wall 73 of a hollow tubular member 72 located coaxially with theoutput shaft 23 is mounted to an inner surface of a central portion ofthe main body 16 of the shell-shaped member 15 with a seal ring 74interposed therebetween. A shorter outer tube portion 75 extendinginwards from an outer periphery of the end wall 73 is connected at itsinner end to the hollow bearing tube 21 of the first half 8 through aconnecting tube 76. A long inner tube portion 77 having a small diameteris provided on the end wall 73 to extend through the end wall 73 andfitted at its inner end into a stepped bore h provided in thelarger-diameter solid portion 66 of the stationary shaft 65 along with ashort hollow connecting pipe 78 protruding from the inner end of theinner tube portion 77. An outer end of the inner tube portion 77protrudes outwards from a bore 79 in the shell-shaped member 15, and araised temperature/pressure vapor-introducing pipe 80 inserted from suchouter end portion through the inner tube portion 77 is fitted at itsinner end into the hollow connecting pipe 78. A cap member 81 isthreadedly fitted over the outer end of the inner tube portion 77, and aflange 83 of a holder tube 82 for retaining the introducing pipe 80 ispress-attached to an outer end face of the inner tube portion 77 by thecap member 81 with a seal ring 84 interposed therebetween.

As shown in FIGS. 2, 4, 5 and 12, the larger-diameter solid portion 66of the stationary shaft 65 is provided with a mechanism for supplyingraised-temperature/pressure vapor through a plurality of, e.g., twelve(in the embodiment) through-bores c defined in series in the hollowshaft 64 and the output shaft 23 to the cylinder members 39 of the firstto twelfth vane piston units U1 to U12 and for discharging a firstdropped-temperature/pressure vapor generated after expansion from thecylinder members 39 through the through-bores c. The mechanism isprovided in the following manner:

As best shown in FIG. 12, first and second bores 86 and 87 are definedin the larger-diameter solid portion 66 to extend in opposite directionsfrom a space 85 communicating with the hollow connecting pipe 78. Thefirst and second bores 86 and 87 open into bottom surfaces of first andsecond recesses 88 and 89 opening into the outer peripheral surface ofthe larger-diameter solid portion 66. First and second seal blocks 92and 93 made of carbon and having supply ports 90 and 91 are mounted inthe first and second recesses 88 and 89, respectively, with their outerperipheral surfaces put into sliding contact with the inner peripheralsurface of the hollow shaft 64. Short first and second supply pipes 94and 95 coaxial with each other are inserted loosely into the first andsecond bores 86 and 87, and tapered outer peripheral surfaces i and j offirst and second seal tubes 96 and 97 fitted over outer peripheralsurfaces of tip ends of the first and second supply pipes 94 and 95 arefitted to inner peripheral surfaces of tapered bores k and m locatedinside the supply ports 90 and 91 in the first and second seal blocks 92and 93 and leading to the supply ports 90 and 91, respectively. Firstand second annular recesses n and o surrounding the first and secondsupply pipes 94 and 95 and first and second blind bore-shaped recesses pand q adjoining the first and second annular recesses n and o aredefined in the larger-diameter solid portion 66 to face the first andsecond seal blocks 92 and 93. First and second bellows-shaped elasticmembers 98 and 99 are accommodated in the first and second annularrecesses n and o, and first and second coil springs 100 and 101 areaccommodated in the first and second blind bore-shaped recesses p and q,respectively, so that the first and second seal blocks 92 and 93 arepushed to the inner peripheral surface of the hollow shaft 64 byrepulsing forces of the first and second bellows-shaped elastic members98 and 99 and the first and second coil springs 100 and 101.

In the larger-diameter solid portion 66, first and second recess-shapeddischarge portions 102 and 103 usually communicating with the twothrough-bores c and first and second discharge bores 104 and 105 aredefined between the first coil spring 100 and the second bellows-shapedelastic member 99 and between the second coil spring 101 and the firstbellows-shaped elastic member 98. The first and second discharge bores104 and 105 extend from the discharge portions 102 and 103 in parallelto the introducing pipe 80 and open into a hollow r of the stationaryshaft 65.

The members of the same type affixed respectively with the terms “first”and “second” such as the first seal block 92 and the second seal block93 are in a point symmetric relation to each other with respect to anaxis of the stationary shaft 65.

The inside of the hollow r of the stationary shaft 65 and the inside ofthe outer tube portion 75 of the hollow tubular member 72 are passages sfor the first dropped-temperature/pressure vapor, and the passages scommunicate with the expansion chamber 20 through a plurality ofthrough-bores t made through the peripheral wall of the outer tubeportion 75.

As shown in FIGS. 2 and 6, first and second inlet bore groups 107 and108 each comprising a plurality of inlet bores 106 arranged radially aredefined in the outer periphery of the main body 11 of the first half 8in the vicinity of opposite ends of a shorter diameter of the rotorchamber 14, so that a second dropped-temperature/pressure vapor having atemperature and a pressure dropped in the expansion chamber 20 isintroduced into the rotor chamber 14 through the inlet bore groups 107and 108. A first outlet bore group 110 comprising a plurality of outletbores 109 is defined in the outer periphery of the main body 11 of thesecond half 9 between one longer-diameter end of the rotor chamber 14and the second inlet bore group 108, so that the outlet bores arearranged radially and circumferentially and communicate with therecovery chamber 29, and a second outlet bore group 111 comprising aplurality of outlet bores 109 is defined in the outer periphery of themain body 11 of the second half 9 between the other longer-diameter endand the first inlet bore group 107, so that the outlet bores 109 arelikewise arranged radially and circumferentially and communicate withthe recovery chamber 29. A third dropped-temperature/pressure vaporhaving a temperature and a pressure further dropped by the expansionbetween the adjacent vanes 42 is discharged from the first and secondoutlet bore groups 110 and 111 into the recovery chamber 29.

The output shaft 23 and the like are lubricated by water, and a passagefor such lubricating water is formed in the following manner: As shownin FIGS. 2 and 4, a water feed pipe 113 is connected to a water feedbore 112 defined in the hollow bearing tube 22 of the second half 9 andis retained on the cover member 26 with a seal member (not shown)interposed therebetween. The water feed bore 112 communicates with ahousing 114 faced by the metal bearing 25 of the second half 9, and thehousing 114 communicates with a water bore u, which is defined in thethicker portion 62 of the output shaft 23 and communicates with aplurality of water grooves v (see also FIG. 12) extending in a directionof a generating line of the outer peripheral surface of the hollow shaft64. Further, the water grooves v communicate with a housing 115 faced bythe metal bearing 25 of the second half 8. An annular recess w isprovided in the inner end face of the thicker portion 62 of the outputshaft 23 to permit the communication of the water bore u with slidingportions between the hollow shaft 64 and the larger-diameter solidportion 66 of the stationary shaft 65.

Thus, the lubrication between the metal bearings 25 and the output shaft23 as well as between the hollow shaft 64 and the stationary shaft 65 isconducted by the water, and the lubrication between the casing 7 andseal member 44 as well as the rollers 59 is conducted by the waterpassed through a gap between each of the metal bearings 25 and theoutput shaft 23 into the rotor chamber 14.

Referring to FIGS. 2 and 4, a smaller-diameter portion 116 which is anend portion of the output shaft 23 protrudes into the recovery chamber29 from a bore 117 provided in the hollow bearing tube 22 of the secondhalf 9, whereby the periphery of the smaller-diameter portion 116 issealed against the outside by the cover member 26. The smaller-diameterportion 116 and the bore 117 are sealed against each other by two sealrings 118. A transmitting shaft 119 of a driven member in the outside ofthe cover member 26 is disposed coaxially with the output shaft 119.

The smaller-diameter portion 116 of the output shaft 23 protruding fromthe second half 9 and the transmitting shaft 119 are connected to eachother by a connecting member, e.g., a magnet-type shaft coupling 120having a simple structure in the embodiment to be able to transmit apower. A structure of such connection is as described below. The covermember 26 is formed of a non-magnetic stainless steel (e.g., JIS SUS304,SUS310, SUS316 or the like) and comprises a larger-diameter tube 121 onthe side of the second half 9, an outer smaller-diameter tube 122 and anintermediate tube 123 located between the larger-diameter tube 121 andthe outer smaller-diameter tube 122. The intermediate tube 123 is formedby superposing two circular flanges 124 and 125 of the larger-andsmaller-diameter tubes 121 and 122 one on another with a gasket 126interposed therebetween and fastening them to each other at a pluralityof circumferential points by bolts 127. On the side of an innerperiphery of the intermediate tube 123, there are a boss 128 and aplurality of reinforcing arms 129 extending radially from the boss 128to an inner peripheral surface of the intermediate tube 123. Thesmaller-diameter tube 122 has smaller-diameter inner tube portion 131extending inwards from a center portion of an end wall 130 of thesmaller-diameter tube 122, and the inside of the smaller-diameter tube122 is divided by a partition wall 132 into two portions; a portionadjacent the recovery chamber 29 and a portion adjacent an outerportion. The boss 128 and the inner tube portion 131 are disposedcoaxially with the output shaft 23.

The magnet-type shaft coupling 120 includes a first component 133disposed within the recovery chamber 29, and a second component 134disposed outside the recovery chamber 29. The first component 133comprises a connecting shaft 135, a magnet holder 136 integral with theconnecting shaft 135, and a permanent magnet 137 retained in the magnetholder 136. The connecting shaft 135 is connected at one end thereof tothe smaller-diameter portion 116 of the output shaft 23 within thelarger-diameter tube 121 through a spline-coupling 138 and supported atthe other end thereof on the boss 128 and the inner tube portion 131with bearings 139 and 140 interposed therebetween, respectively. Themagnet holder 136 has an annular plate 141 connected at its innerperiphery to the bearings 139 and 140 of the connecting shaft 135. Asmaller-diameter tube portion 142 is projectingly provided at a radiallyintermediate portion of the annular plate 141 to surround the inner tubeportion 131. The permanent magnet 137 is of a hollow cylindrical shapeand has a bore 143 fitted over the smaller-diameter tube portion 142 andcoupled to an outer peripheral surface of the smaller-diameter tubeportion 142. The permanent magnet 137 also has an annular end face 144coupled in an abutting manner to a half of an outer periphery of theannular plate 141. Thus, the outer peripheral surface of the permanentmagnet 137 is in proximity to the inner peripheral surface of thesmaller-diameter tube 122 made of a non-magnetic stainless steel capableof transmitting a magnetic force therethrough. The permanent magnet 137may comprise a plurality of N-pole pieces and a plurality of S-polepieces alternately arranged in an annular configuration and may becoupled to the outer peripheral surface of the smaller-diameter portion142 and the half of the outer periphery of the annular plate 141.

The second component 134 is comprised of a connecting shaft, a magnetholder 145 integral with the connecting shaft, and a permanent magnet146 retained in the magnet holder 145, basically as is the firstcomponent 133, but in the embodiment, the transmitting shaft 119 alsoserves as the connecting shaft. The transmitting shaft 119 is supportedat one end thereof on the inner tube portion 131 with a bearing 147interposed therebetween. The magnet holder 145 includes an annular endplate 148 whose inner periphery is connected to the transmitting shaft119, and a larger-diameter tube portion 149 connected to an outerperipheral edge of the annular end plate 148 to surround thesmaller-diameter tube 122 with a predetermined distance lefttherebetween. The permanent magnet 146 is of a hollow cylindrical shapeand fitted into the larger-diameter tube portion 149 with its outerperiphery coupled to an inner peripheral surface of the larger-diametertube portion 149. An annular end face 150 is also coupled in an abuttingmanner to an inner surface of an outer periphery of the annular endplate 148. Thus, the permanent magnet 146 has an inner peripheralsurface located in proximity to the outer peripheral surface of thesmaller-diameter tube 122 capable of transmitting a magnetic forcetherethrough, and surrounds the permanent magnet 137 of the firstcomponent 133 with the smaller-diameter tube 122 interposedtherebetween. Therefore, the smaller-diameter portion 116 of the outputshaft 23 and the transmitting shaft 119 are connected to each other byattracting forces of the permanent magnets 137 and 146. The permanentmagnet 146 may comprise a plurality of N-pole pieces and a plurality ofS-pole pieces alternately arranged in an annular configuration and maybe coupled to the inner peripheral surface of the larger-diameter tubeportion 149 and an inner surface of an outer periphery of the annularend plate 148.

Both of the first component comprising the plurality of reinforcing arms129 and the bearing 139 and the second component comprising the bearing140 and a substantial half of the inner tube portion 131 retaining thebearing 140 are not necessarily required, and one of the components maybe omitted.

If the cover member 26 and the magnet-type shaft coupling 120 are usedas described above, the output shaft 23 and the transmitting shaft 119of the driven member can be connected to each other with the peripheryof the smaller-diameter portion 116 of the output shaft 23 sealed, sothat a power can be transmitted.

In the recovery chamber 29, a space is provided between the second half9 of the expander 4 and the permanent magnet 137 to communicate with theduct 30. Therefore it is possible to inhibit the propagation of heat ofthe heated expander 4 to the permanent magnet 137 to prolong the life ofthe permanent magnet 137.

Further, the smaller-diameter tube 122 retains the connecting shaft 135and the transmitting shaft 119 coaxially, with the bearings 140 and 147interposed therebetween. Therefore, the permanent magnet 137 on the sideof the connecting shaft 135 and the permanent magnet 146 on the side ofthe transmitting shaft 119 can be disposed concentrically, and aclearance between the permanent magnets 137 and 146 can be maintaineduniformly over the entire peripheries of the permanent magnets 137 and146, whereby the transmission of the power can be carried out smoothly.

If the first component including the reinforcing arms 129 is omitted,then it is easy to align the connecting shaft 135 and the transmittingshaft 119 with the output shaft 23, because the smaller-diameter tube122 retaining the connecting shaft 135 and the transmitting shaft 119coaxially is fixed by the bolts 127.

Likewise, if the first component including the reinforcing arms 129 isomitted, then a sufficient rigidity can be provided to thesmaller-diameter tube 122 retaining the two shafts 135 and 119, if thecover member 26 is formed of a non-magnetic stainless steel.

Further, if the second component including the bearing 140 is left oromitted, then the rigidity of the smaller-diameter tube 122 can bereduced, if the connecting shaft 135 is supported on the boss 128 of thereinforcing arms 129 with the bearing 139 interposed therebetween.Therefore, the smaller-diameter tube 122 can be formed of a lightweightmaterial having an excellent corrosion resistance such as a syntheticresin.

Yet further, if the cover member 26 is formed in a combinationcomprising the larger-diameter tube 121 and the smaller-diameter tube122, then the assemblability of the relatively heavy magnet-type shaftcoupling 120 can be improved. For example, the assembling of themagnet-type shaft coupling 120 is carried out sequentially by connectingthe first component 133 to the output shaft 23, fastening thesmaller-diameter tube 122 to the larger-diameter tube 121 and couplingthe second component 134 to the smaller-diameter tube 122.

Referring to FIG. 5, the first and seventh vane piston units U1 and U7having a relationship of point symmetry to each other with respect tothe rotational axis L of the rotor 31 are operated in a similar manner.This also applies to the second and eighth vane piston units U2 and U8having a relationship of point symmetry to each other.

For example, referring also to FIG. 12, an axis of the first supply pipe94 is slightly deviated in a counterclockwise direction as viewed inFIG. 5 from a shorter-diameter position E of the rotor chamber 14, andthe first vane piston unit U1 is located in the shorter-diameterposition E, and the raised-temperature/pressure vapor is not supplied toa larger-diameter cylinder bore f in the first vane piston unit U1.Therefore, the piston 41 and the vane 42 are in their retractedpositions.

When the rotor 31 is slightly rotated from this state in thecounterclockwise direction, the supply port 90 in the first seal block92 and the through-bore c are put into communication with each other,whereby the raised-temperature/pressure vapor is introduced from theintroduction pipe 80 into the larger-diameter cylinder bore f throughthe smaller-diameter bore b. This causes the piston 41 to be advanced,and this advancing movement of the piston 41 is converted into therotating movement of the rotor 31 by the sliding movement of the vane 42to a longer-diameter position F in the rotor chamber 14. If thethrough-bore c is deviated from the supply port 90, theraised-temperature/pressure vapor is expanded within the larger-diametercylinder bore f to further advance the piston 41, whereby the rotationof the rotor 31 is continued. When the first vane piston unit U1 reachesthe longer-diameter position F in the rotor chamber 14, the expansion ofthe raised-temperature/pressure vapor is finished. Thereafter, the firstdropped-temperature/pressure vapor within the larger-diameter cylinderbore f is discharged via the smaller-diameter bore b, the through-borec, the first recess-shaped discharge portion 102, the first dischargebore 104, the passage s (see FIG. 4) and the through-bore t into theexpansion chamber 20 with the rotation of the rotor 31 due to theretraction of the piston 41 by the vane 42. The seconddropped-temperature/pressure vapor generated by the further expansion ofthe first dropped-temperature/pressure vapor in the expansion chamber 20and having a dropped temperature and pressure is introduced into therotor chamber 14 through the first inlet bore group 107, as shown inFIGS. 2 and 6 and further expanded between the adjacent vanes 42 torotate the rotor 31. Thereafter, a third dropped-temperature/pressurevapor is discharged into the recovery chamber 29 through the firstoutlet bore group 110. In this manner, an output power is provided fromthe output shaft 23 by operating the piston 41 by the expansion of theraised-temperature/pressure vapor to rotate the rotor 31 through thevane 42 and by expanding the dropped-temperature/pressure vapor due tothe dropping of the pressure of the raised-temperature/pressure vapor torotate the rotor 31 through the vane 42. Such output power istransmitted to the transmitting shaft 119 through the magnet-type shaftcoupling 120.

If the raised-temperature/pressure vapor is leaked from the sealedportion of the output shaft 23 in the casing 7, namely, from thepositions of the two seal rings 118, such raised-temperature/pressurevapor is recovered by the cover member 26 and hence, cannot be leaked tothe outside. Further, the collected raised-temperature/pressure vapor isconverted into the dropped-temperature/pressure vapor within the covermember 26, namely, within the recovery chamber 29. Suchdropped-temperature/pressure vapor is fed to the condenser 5 along withthe third dropped-temperature/pressure vapor fed from the outlet bore109. Thus, it is possible to avoid the reduction in amount of theoperating medium to maintain the Rankin cycle.

FIG. 13 shows an example in which the condenser 5 is disposed adjacentthe expander 4. In this case, the cover member 26 also serves as ahousing for the condenser 5, and the smaller-diameter portion 116 of theoutput shaft 23 in the expander 4 is connected to the connecting shaft135 of the first component 133 in the magnet-type shaft coupling 120through a long shaft 151 extending within the housing of the condenser5. In this example, the heavy condenser 5 can be assembled to theexpander 4 and then, the magnet-type shaft coupling 120 can be assembledin the same manner as described above. Therefore, a further remarkableeffect is provided by forming the cover member 26 in a combined manner.Portions or components in FIG. 13 corresponding to those in FIG. 3 aredesignated by like reference numerals and characters, and the detaileddescription of them is omitted.

In an expander in which an energy of expansion of a vapor having araised pressure is converted into a rotating energy for an output shaft,a cover member is mounted on an outer surface of a casing of theexpander. The cover member has a function of sealing an end of theoutput shaft protruding on the outer surface of the casing against theoutside and a function of recovering vapor discharged from the casingand having a dropped pressure after the conversion. The end of theoutput shaft located within the cover member and a transmitting shaft ofa driven member disposed outside the cover member are connected to eachother through a magnet-type shaft coupling, so that a power can betransmitted. Thus, the output shaft and the transmitting shaft of thedriven member can be connected to each other to prevent the leakage ofthe vapor in the expander to the outside.

What is claimed is:
 1. A structure of connection between an output shaftof an expander and a transmitting shaft of a driven member, comprising:an output shaft; a power transmitting member; and a cover member mountedto a flange extending from an outer surface of an expander casing,wherein said cover member is disposed entirely between said casingflange and said power transmitting member, wherein expansion energy of avapor having a raised pressure is converted into a rotating energy forthe output shaft, wherein said cover member seals an end of said outputshaft protruding from the outer surface of said casing, and recoversvapor discharged from said casing, wherein said discharged vapor has adropped pressure after said conversion, and wherein said powertransmitting member transmits power non-contactingly between the end ofsaid output shaft located within said cover member and the transmittingshaft of the driven member disposed outside said cover member, wherein apower can be transmitted.
 2. A structure of connection between an outputshaft of an expander and a transmitting shaft of a driven memberaccording to claim 1, wherein said power transmitting member is amagnet-type shaft coupling.
 3. A structure according to claim 1, whereinsaid cover member defines a dropped-temperature/pressure recoverychamber between said casing and said power transmitting member.
 4. Astructure according to claim 1, wherein said casing is tubular in shape.5. A structure according to claim 1, wherein a first diameter of saidcover member at an end mounted to said casing is larger than a seconddiameter of said cover member at another end closest to said powertransmitting member.
 6. A structure according to claim 1, wherein saidcover member includes a flange corresponding to said flange of saidcasing.
 7. A structure according to claim 6, wherein said flanges areconnected by at least one fastening member.
 8. A structure according toclaim 7, wherein said at least one fastening member is a bolt.